A 3200-g (7.1-lb) female newborn is examined in the hospital nursery. She was born at 38 weeks' gestation to a 25-year-old woman following an uncomplicated pregnancy and delivery. The mother had regular prenatal visits throughout the pregnancy. The newborn's blood pressure is 53/35 mm Hg. Examination in the delivery room shows clitoromegaly and posterior labial fusion. . Cytogenetic analysis reveals a 46,XX karyotype. Abdominal imaging shows bilateral adrenal hyperplasia. This patient is most likely deficient for an enzyme normally responsible for which of the following reactions?

Question

A 3200-g (7.1-lb) female newborn is examined in the hospital nursery. She was born at 38 weeks' gestation to a 25-year-old woman following an uncomplicated pregnancy and delivery. The mother had regular prenatal visits throughout the pregnancy. The newborn's blood pressure is 53/35 mm Hg. Examination in the delivery room shows clitoromegaly and posterior labial fusion. .  Cytogenetic analysis reveals a 46,XX karyotype.  Abdominal imaging shows bilateral adrenal hyperplasia.  This patient is most likely deficient for an enzyme normally responsible for which of the following reactions?

Quizplus · Accepted Answer

Eductional Objective: The most common form of congenital adrenal hyperplasia is 21-hydroxylase deficiency.  Genetically female infants typically have ambiguous genitalia (virilization) at birth, whereas males have phenotypically normal genitalia, with salt-wasting or precocious puberty appearing later.  Elevated 17-hydroxyprogesterone is diagnostic.

A 3200-G (7